JPS6034512B2 - calcareous ramming material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a calcareous clinker obtained by competitively using high-purity calcareous raw materials with few impurities such as Si02, Fe203 and Tj02, or a calcareous clinker and a magnesia clinker,
This invention relates to a lime ramming material in which a water-insoluble binder is added to a mixture prepared by mixing with dolomite clinker or the like at a certain ratio.

Ca○ (calcium oxide) has a very high melting point (2$7±
270), it is effective when used as a refractory material, and is particularly stable at high temperatures with low vapor pressure, making it suitable for melting clean metals with few inclusions at high temperatures and reduced pressure. It is.

However, calcareous refractory materials have traditionally only been used for part of the lining of cement rotary kilns, Kendo furnaces, Tortoise arc furnaces, and glass furnaces, and the reason for this is that Ca○ is The problem was that it reacted with water to produce calcium hydroxide, which resulted in poor shelf life.

Therefore, in order to overcome this drawback, conventional Ca0, for example, F
Impurities such as e203, Ti02, and Si02 are added as stabilizing agents against digestion in order to obtain a calcareous clinker that is resistant to digestion. process and mixing process)
Although it takes a lot of time and money to add a considerable amount of impurities (5% or more), as is done industrially, a low melting point compound is formed between the added impurities and the fire resistance and Another problem arose when the insect resistance deteriorated.

In view of these facts, the present inventors repeatedly conducted experiments on calcining and digestion of calcareous raw materials, and found that the Ca0 content was 95% by weight or more (97.5%) after ignition loss measurement.
Fe203, T
The present invention was completed by discovering that it has good digestion resistance and can be used industrially without adding impurities such as i02 and Sj02. Limestone, quicklime or treetop lime with a Ca○ content of 95% by weight or more is 1600
00 or more, preferably 1,600 to 180,000, and held at that temperature for at least 1.5 hours, preferably 2 to 6 hours, and then cooled at a slow rate of 100 degrees Celsius or less per hour to determine the crystal grain size of Ca○. This means that 3 to 40 Buddhas of clinker can be obtained. <The produced calcareous clinker can not only be used alone, but also one or more types of magnesia clinker, natural dolomite clinker, or synthetic magnesia dolomite clinker can be added to it in an amount of 45% by weight of the total amount after mixing. %, the particle size is adjusted so that close packing can be obtained in each case, and alcohol, polypden, asphalt, pitch, wax, /grafine, polypropylene, modified acrylic resin,
Phenolic resin, coal tar and bears. By adding a known water-insoluble organic binder such as a water-insoluble organic binder, and kneading it under heating or at room temperature using a kneading machine such as a wet pan mixer, a calcareous material with excellent digestibility and corrosion resistance is produced. The ramming material is obtained. Here, the reason why the content of Ca○ is set to be 95% by weight or more (preferably about 97.5% by weight) after ignition loss is that if it is less than 95% by weight, many glass layers will form between the particles. is generated, the number of sealed pores increases, the mechanical strength of the ramming material decreases, and the corrosion resistance increases.
Furthermore, the reason why the crystal grain size of Ca○ should be 3 to 40 degrees is because if it is less than 3 degrees, the reactivity with moisture increases and the digestibility decreases, and if it exceeds 40 degrees, it will reduce the spall resistance. This is because spalling is likely to occur due to the influence of heat during use as a refractory.

In addition, the limit for mixing one or more of magnesia clinker, natural dolomite clinker, and synthetic magnesia dolomite clinker with calcareous clinker has been set to 4.
The reason why the content is 5% by weight or less is that when added up to this amount, corrosion resistance and spalling resistance are particularly improved, but when added more than that, spalling resistance decreases and the properties of calcareous clinker cannot be exhibited. It is from. The results of comparative tests of the calcareous ramming material of the present invention with conventional products will be explained in detail below. Calcareous clinkers having the chemical composition and crystal grain size shown in Table 1 were used, and
After mixing the coarse grains and pongee grains in a wet pan mixer and mixing them, the binder is added and thickened, and then the characteristic powder is added and thoroughly kneaded. 6 types of ramming materials of the present invention and 2 conventional products obtained by
Depending on the type, the upper side is 4 sails, the lower side is 6 sails, and the height is 5 sails.
Two blocks each with a trapezoidal cross section and a length of 100 fences were stamped and brazed at 1,300 oo, then these two blocks were assembled and lined in a total of 16 rotating drums, and then slag and A so-called rotary erosion test was conducted at 700° C. for 5 hours to measure the dimensions of erosion.

In addition, regarding the measurement of spalling resistance (thermal shock resistance number of times), using the chemical composition and crystal grain size shown in Table 1,
Using the ramming material obtained with the compounding ratio shown in the table, two blocks each with a length of 5 ribs, a width of 5 ribs, and a length of 150 ribs were formed, and fired at 1300 o'clock to prepare specimens. Insert these into the electric furnace in the length direction for 5 yards, and at 1400oo
After holding for a minute, it is taken out and air cooled for 18 minutes. The number of times this operation was repeated until the heated part of the test piece collapsed and fell off was defined as the number of times of thermal shock resistance, and the average value of the two values is shown. Furthermore, the digestion resistance is measured by the weight increase rate, and the method is to fill the same ramming material as above into cubic containers of appropriate volume without top lids, and to store them at a temperature of 25 oo and a humidity of 70%.
It was inserted into a constant temperature humidity tank and taken out on the 50th day, and the weight increase rate due to hydration was measured.

The above results show that the erosion dimension, which represents corrosion resistance, the weight increase rate, which represents digestion resistance, and the thermal shock resistance, which represents spalling resistance, are all as shown in Table 2 for the specimen N according to the present invention.
○, 1 to 6 are obviously conventional specimens N○, 7 to 8
It showed a marked improvement in characteristics compared to the previous one.

Next, as an actual furnace test of the ramming material of the present invention, the ramming material was stamped evenly on the hearth of a 3-ton electric furnace, and 180 tons, which is the same total number of smelted tons as in the past, was smelted. Comparison tests were conducted with cases in which the residual thickness of the ramming material for composition example sail ○ and 1 of the present invention was 20 to 27 more than that of composition example sail 08, which was a conventional product, that is, the corrosion resistance was 11 to 1. It was confirmed that there was an improvement of 15%, and at the same time, there were no signs of digestion, and almost no cracking or peeling phenomena were observed.

Furthermore, when compounding examples N○, 1 and N○, 3 of the present invention were stamped by half-stretching on the hearth of an electric furnace of the same capacity, it became possible to process a total of 135 tons of refining, which made it possible to process with conventional products. It shows a good result with about 10% more thickness than this, and if you look closely, the residual thickness of N○, 3 is 5 to 15 more than that of N0, 1, and in terms of corrosion resistance, it is superior to magnesia. It has been proven that good results can be obtained by blending.

When we cut out the steel treated in these actual furnace operations and examined the oxide inclusions in the steel, we found that there were fewer inclusions compared to the steel treated with conventional products. It was also confirmed that the number of ships leaving port due to reactions was small.

As described above, the present invention eliminates the disadvantages of calcareous refractory materials, which have been recognized for their advantages but had limitations in use due to their accompanying disadvantages, and provides highly effective characteristics. The industrial effects of expanding the range of utilization are significant.
Table 1 All methods for measuring crystal grain sizes were carried out in accordance with the Gakushin method (Refractories Tehari No. 296-29 Toji, published in 1971).

Table 2 (Note 1) In the binder, P represents polybutene and W represents wax, and the amounts added are indicative.

Claims (1)

[Claims] 1. A water-insoluble organic binder is added to a calcareous clinker that has been hard-fired and adjusted in grain size so that the CaO content is 95% by weight or more and the crystal grain size is 3 to 40μ. death,
Calcareous ramming material obtained by mixing and kneading. 2 Calcareous clinker with a CaO content of 95% by weight or more and a crystal grain size of 3 to 40μ, and 45% by weight or less of magnesia clinker, natural dolomite clinker, synthetic magnesia dolomite clinker. A calcareous ramming material obtained by adding a water-insoluble organic binder to a blended product whose particle size has been adjusted after mixing one type or two or more types, and then mixing and kneading the mixture.